do you take any vitamins or supplements?
{if so make sure nothing interacts with any of your meds}

But at the very least maybe a good multiple vitamin, stress B complex, Vit C, Cal /Mag blend, some RSDers suggest Grape Seed Extract & I recomend MSM.

I really swear by the EmerGenC stuff we take it as soon as we start getting the scratchy throat & sneezes.
1000mg of Vit plus other stuff in a packet - pour it into a glass of water and it fizzes to dissolve then drink.